Tax completion certificate and receipt

I am a foreign resident that currently lives and works in the UK. Tax department at my country has required me to provide tax completion certificates and tax receipts. Where can I apply for these documents please?

Hi,
If you are employed under PAYE this will be your payslips/P60.
If self employed this will be a copy of your tax return to show income and your statement to show the tax has been paid.
Thank you.